This invention relates to a dynamoelectric machine, and more particularly, to an induction electric motor, having its endshield so structured that when the endshield is facing generally upwardly, the water dripping thereon is directed radially outwardly away from the motor for discharge at a location in which the water will not come into contact with the stator or the windings of the motor.
More specifically, in certain motor applications, such as in dishwasher applications, the motor is mounted to the bottom face of a dishwasher tub or the like, and the rotor shaft of the motor extends vertically into a dishwasher pump or the like. A seal is typically fitted around the rotor shaft so as to prevent water from within the dishwasher from leaking past the seal and falling onto the motor. In the past, small amounts of water (and more specifically, dishwashing detergent solution) may, on occasion, leak past these seals. This leakage may not be sufficient as to cause the homeowner to notice leaking water from the dishwasher. However, the leaking water running down the shaft could have a deleterious effect on the motor.
It had been known to fix a splash guard, such as a disc, to the rotor shaft of the motor between the seal on the rotor shaft and the rotor bearing carried by the endshield. Water leaking past the seal would encounter the drip or splash guard, and would be directed radially outwardly away from the bearing, thus preventing the water from falling directly on the bearing. However, when the water dripped from the drip guard onto the endshield out beyond the bearing, the water would flow generally horizontally, outwardly on the upwardly facing surface of the endshield away from the bearing, until it encountered the edge of the endshield. The water would then flow downwardly along the sides of the endshield. However, since it is conventional to diecast endshields of a suitable metal alloy in a two-part diecasting mold, when the water encountered the parting line formed by the mold halves on the side of the diecasting, the surface tension of the water would cause the water to follow the parting line in a generally downward direction. Oftentimes, the water following the parting line on the sides of the diecasting would be directed onto the end turns of the windings of the motor, and onto the stator iron. Over time, this dripping water on the stator and on the end turns could lead to failure of the motor.
Heretofore, in order to prevent the water from following the parting line on the endshield, it was known to form a step in the parting line. This step in the parting line would disrupt the flow path of the water following the parting line and would cause the water to drip from the parting line at a desired location. However, in order to form the step in the parting line, changes to the diecasting molds were necessary which increased their complexity and expense.